What is the correct angle for intramuscular (IM) injections?

When administering intramuscular (IM) injections, the correct angle is 90 degrees. This angle is essential because it allows the needle to penetrate the muscle tissue directly, ensuring that the medication is deposited where it can be absorbed effectively. Muscles are thicker and have a greater blood supply than other tissues, which facilitates quicker absorption of the injected substance.

Injecting at a 90-degree angle helps avoid tissue damage and ensures that the medication is not injected into subcutaneous fat instead of the muscle. This is particularly important for medications that are meant to be delivered intramuscularly for systemic effects. Additionally, the 90-degree angle is commonly practiced for IM injections in various muscle sites, including the deltoid, vastus lateralis, and ventrogluteal muscles.

Choosing an angle lower than 90 degrees, such as 45, 30, or 15 degrees, may result in improper administration, leading to inadequate absorption or causing injury to surrounding tissues, nerves, or blood vessels. Therefore, the practice of using a 90-degree angle is crucial for the safety and effectiveness of IM injections.